Ravenna Creek stream flow transfer pipeline

Completed – Winter 2004

King County's Wastewater Treatment Division has installed a new pipeline in some sidewalks between NE 54th St and NE 45th St in Seattle. When completed, this joint King County/City of Seattle project will take clean water from Ravenna Creek that flows into a sewer line and move it into a new pipe to 45th NE and into Lake Washington.

The creek flows are now treated unnecessarily at King County's West Point Treatment Plant in northwest Seattle. Moving them through the new pipe will reduce costs and make room within the sewer system. The new pipe connects with an existing city storm drain to Lake Washington.

Ravenna Creek – history and other projects

Ravenna Creek used to flow from Green Lake to Lake Washington through the current location of Cowen and Ravenna parks. Because of development, the creek was diverted into a sewer pipe and now exists aboveground only within Ravenna Park, where it is fed by springs and runoff.

Since 1990, plans to restore the creek to the surface (called "daylighting") within the park boundaries have been in development. King County will transfer the creek into a new pipeline, and the City of Seattle will daylight a portion of the creek within Ravenna Park.

What did construction involve?

Construction ran from September 2003 to February 2004

A King County contractor installed an 18-inch pipe in the sidewalk from NE 54th along 24th Ave NE; along Ravenna Place NE to the intersection with NE Blakely St; and along 25th Ave NE to a location just north of NE 45th.

The contractor worked in 300-foot sections every two weeks, restoring each section before moving to the next.

During construction, King County's contractor worked to preserve access to businesses. To keep traffic flowing on 25th NE, the contractor installed the pipeline in the sidewalk. Construction affected street parking in the area. The contractor avoided construction on weekends.